In recent years, rapid advances have been made in digitalization of information. This has led to remarkable efforts to meet with this in the imaging field.
In particular, as symbolized by the digital camera, in the imaging surfaces, the conventional film is being taken over by use of solid-state imaging devices such as CCDs (Charge Coupled Devices) or CMOS (Complementary Metal Oxide Semiconductor) sensors in most cases.
An imaging lens apparatus using a CCD or CMOS sensor for the imaging device in this way optically captures the image of an object by the optical system and extracts the image as an electric signal by the imaging device.
Other than a digital still camera, this type of imaging lens apparatus is used in a video camera, a digital video unit, a personal computer, a mobile phone, a personal digital assistant (PDA), an image inspection system, an automatic control use industrial camera, and so on.
FIG. 1 is a view schematically showing the configuration of a general imaging lens apparatus and a state of light beams.
This imaging lens apparatus 1 has an optical system 2 and a CCD or CMOS sensor or other imaging device 3.
The optical system includes object side lenses 21 and 22, a stop 23, and a joining lens 24 sequentially arranged from the object side (OBJS) toward the imaging device 3 side.
In the imaging lens device 1, as shown in FIG. 1, the best focus plane is made to match with the imaging device surface.
FIG. 2A to FIG. 2C show spot images on a light receiving surface of the imaging device 3 of the imaging lens apparatus 1.
Further, imaging apparatuses using phase plates to regularly disperse the light beams, using digital processing to restore the image, and thereby enabling capture of an image having a deep depth of field and so on have been proposed (see for example Non Patent Documents 1 and 2 and Patent Documents 1 to 5).
Further, an automatic exposure control system of a digital camera performing filter processing using a transfer function has been proposed (see for example Patent Document 6).
Further, in CCDs, CMOS's, and other devices having image input functions, it would often be extremely useful to read barcodes and other close still images together with a scene or other desired image.
For reading a barcode, for example, the technique of focusing by auto-focus moving the lens outward as a first example and a technique of depth extension as a second example reducing the F value in a camera to extend the depth of field and fix the focus are known.    Non Patent Document 1: “Wavefront Coding; jointly optimized optical and digital imaging systems”, Edward R. Dowski, Jr., Robert H. Cormack, Scott D. Sarama.    Non Patent Document 2: “Wavefront Coding; A modern method of achieving high performance and/or low cost imaging systems”, Edward R. Dowski, Jr., Gregory E. Johnson.    Patent Document 1: U.S. Pat. No. 6,021,005    Patent Document 2: U.S. Pat. No. 6,642,504    Patent Document 3: U.S. Pat. No. 6,525,302    Patent Document 4: U.S. Pat. No. 6,069,738    Patent Document 5: Japanese Patent Publication (A) No. 2003-235794    Patent Document 6: Japanese Patent Publication (A) No. 2004-153497